Trump has said that he is under audit by the IRS and maintained
throughout the 2016 cycle that it would be unwise to release his
tax documents until the audit is complete.

His critics, however, have continued to hit him on the topic.

Throughout the primary season, Trump's rivals seized on the
issue. In May, 2012 GOP nominee
Mitt Romney speculated that there could be a "bombshell of
unusual size" in the returns and said "it is disqualifying for a
modern-day presidential nominee to refuse to release" them.

Clinton's questioning of Trump's fortune came just hours after
billionaire investor Mark Cuban also
expressed doubt that the real-estate mogul is as wealthy as
he claims.